This invention relates to the construction in which handles for operating a portable chain saw or other portable machine which has a built-in vibration producing source are mounted such that vibrations produced by the vibration producing source (hereinafter referred to as the engine) is absorbed through vibration absorbing means.
Generally, a fuel tank, an oil tank, a chain saw blade actuating section and the engine for driving the saw blade constitute a main body of a sawing machine of this type in order to obtain an overall compact size. Usually, the sawing machine of this type has attached thereto through vibration absorbing means a rear handle for deciding the direction of movement of the chain saw blade and a front handle for supporting the main body when a sawing operation is performed.
The rear handle is intended to perform the function of maintaining the chain saw blade in a predetermined position, in a predetermined posture and in a predetermined direction when a sawing operation is performed, so that the rear handle has only to be gripped with a force of relatively low intensity. On the other hand, the front handle is disposed near the center of gravity of the main body of a chain saw and mainly intended to support the weight of the main body. Thus, the front handle must be mounted such that it can readily cope with a change in the posture of the main body and at the same time satisfactorily absorb vibration of the main body.
In view of the aforementioned functions of the handles, several types of chain saws including handles constructed to absorb vibration have hitherto been developed. However, none of them have been satisfactory in operation.